Year	%
1989	25.3
1991	24.2
1995	21.2
1996	21.9
1998	26.9
1999	24.4
2000	23.3
2001	23.6
2002	23.6
2003	24.1
2004	20.9
2005	21.3
2006	18.2
2007	16.2
2008	18.6
2009	18.5
2010	18.3
2011	16
2012	15.7
2013	16.3
2014	15.6
2015	14.4
2016	16.3
2017	14.5
2018	15.3
2019	14.6
2021	17
2022	16.9